1. Technical Field
This invention relates to a system which uses smart cards, and more particularly, to a system which uses smart cards for processing and communicating data while in a mobile environment.
2. Description of the Prior Art
Wireless technology is fueling a major revolution in communications. This technology allows new access connections to landline networks. However, the impact of wireless is far more profound than simply being another method of access. Wireless technology allows the customer to have mobility in his or her communications and not be constrained to the tether of wired access. Wireless technology also permits the customer to gain access to an application from wherever he or she wishes, within the constraints of wireless network deployment and range.
What is still in its infant stages, however, is wireless communications which enables a user of a smart card-like device to become completely untethered when using such a device in short range wireless communications.
A number of proposals have been made with regard to providing a customer with a wireless connection for performing various financial transactions. One such proposal, for example, is described in U.S. Pat. No. 4,977,501 which issued to J. P. Lefevre on Dec. 11, 1990. This patent describes a fare collection system for operators of transport vehicles wherein information is periodically exchanged at microwave frequencies between a smart card-like ticket, held by a passenger in the vehicle, and a transceiver also in the vehicle. A credit balance initially assigned to the ticket is decremented by circuitry in the transceiver which interrogates the ticket.
Other proposals have also been made with regard to providing a holder of a smart card-like device with an identifying radio frequency signal which uniquely identifies the individual holder of the device. One proposed wireless system for providing a radio frequency emitting identifier is described in U.S. Pat. No. 4,384,288 issued to C. A. Walton on May 17, 1983. This patent describes an electronic identification system comprising a credit card-shaped identifier which generates a programmable pulse position-modulated signal in the radio frequency range for identification of the user.
It is becoming increasingly necessary to quickly and accurately identify people located at a terminal remote to a central processing station. Such identification is necessary for making financial transactions or for expediting the movement of people through electronic barriers. In such systems, the identification must be accurate and, to conserve computer time, done relatively quickly.
As wireless communication matures, it will become more and more likely that multiple smart card-like devices will be in radio range of a communication terminal thereby causing destructive interference, even if only short range communications are allowed. It is desirable, therefore, to have a wireless interrogatable and updatable system which supports multiple smart card-like devices within radio range without destructive interference.